A method and system for identifying and optimizing a CFD conflict coupling area of an exhaust muffling unit

Abstract

This application relates to the field of design optimization technology, and discloses a CFD-based method and system for identifying and optimizing the conflict coupling zone of an exhaust muffler unit. The method includes: acquiring the muffler unit structural model and boundary conditions of the target exhaust system; performing fluid numerical simulation to generate local pressure loss distribution results; determining the corresponding pressure loss contribution results based on the local pressure loss distribution results; performing acoustic simulation based on the muffler unit structural model and acoustic boundary conditions to generate acoustic response results for the target frequency band, and determining the acoustic contribution results corresponding to each local region; performing overlap determination based on the pressure loss contribution results and acoustic contribution results to identify the conflict coupling zone; generating regional adjustment constraints based on the local structural parameters corresponding to the conflict coupling zone, and performing structural parameter optimization based on the regional adjustment constraints to generate the target optimized structural result. This application can improve the collaborative optimization capability of the exhaust muffler unit's pressure loss and target frequency band acoustic performance.

Description

Technical Field

[0001] This application relates to the field of design optimization technology, and more specifically, to a method and system for identifying and optimizing the CFD conflict coupling zone of an exhaust muffler unit. Background Technology

[0002] The muffler unit in the exhaust system must meet the noise attenuation requirements of the target frequency band while controlling the pressure loss in the exhaust passage to avoid adverse effects on the overall exhaust efficiency and power response. In existing technologies, a muffler unit structural model is usually established, and fluid numerical simulation and acoustic simulation are performed separately to obtain the overall pressure loss results and overall acoustic performance results. Then, the structural parameters of the muffler unit are adjusted based on the overall evaluation results. Although this method can take into account both flow resistance performance and noise reduction performance to a certain extent, its analysis objects are mostly limited to the overall structural level. It usually only obtains the overall pressure drop index and the overall target frequency band attenuation index, without further dividing the internal space of the muffler unit into local areas that can be uniformly compared, and without generating pressure loss contribution results and acoustic contribution results for each local area.

[0003] Because of the lack of pressure loss and acoustic contribution results for each local region, existing methods struggle to determine whether a region simultaneously belongs to a high pressure loss and high acoustic contribution region within the same local area. Consequently, it is difficult to identify conflicting regions with both high pressure loss and high acoustic contributions from within the anechoic unit. As a result, when certain local structures participate in the formation of target frequency band attenuation on the one hand, and induce local backflow, eddies, or high-speed contraction on the other hand, existing optimization processes often still use the overall structural parameters as a unified adjustment object, lacking a separate analytical basis for conflicting regions.

[0004] Furthermore, since conflict regions are not identified beforehand, existing methods struggle to develop targeted adjustment directions and ranges for local structural parameters within these conflict regions during subsequent structural optimization. They typically rely on repeated searches and multiple rounds of trial adjustments driven by overall performance indicators. This can easily lead to situations where local pressure loss is amplified to increase attenuation in a certain frequency band, or key acoustic attenuation paths are weakened to reduce pressure loss. Consequently, the structural optimization process lacks clear regional specificity, affecting both overall optimization efficiency and the stability of optimization results.

[0005] Therefore, how to identify local conflict areas within the exhaust muffler unit that simultaneously contribute significantly to both pressure loss and acoustic performance during the optimization process, and how to use this information to support targeted optimization of subsequent structural parameters, has become a pressing technical problem in this field. Summary of the Invention

[0006] To overcome the aforementioned deficiencies of existing technologies and achieve the above objectives, this application provides the following technical solution: Fluid numerical simulation and acoustic simulation are performed on the structural model of the muffler unit to generate local pressure loss distribution results, pressure loss contribution results, target frequency band acoustic response results, and acoustic contribution results, respectively. Overlap determination is then performed on a unified local region object to identify conflict coupling zones. Furthermore, based on these conflict coupling zones, regional adjustment constraints are generated, and structural parameter optimization is performed, forming a constrained optimization processing chain oriented towards local conflict regions. This improves the targeted synergistic optimization between pressure loss control and target frequency band acoustic performance of the exhaust muffler unit.

[0007] A method for identifying and optimizing the CFD conflict coupling region of an exhaust muffler unit includes:

[0008] Obtain the structural model and boundary conditions of the muffler unit of the target exhaust system under set operating conditions, and perform fluid numerical simulation to generate local pressure loss distribution results;

[0009] Based on the local pressure loss distribution results, the pressure loss contribution results corresponding to each local region in the silencing unit structure model are determined.

[0010] Based on the aforementioned anechoic unit structure model and acoustic boundary conditions, acoustic simulation is performed to generate acoustic response results for the target frequency band.

[0011] Based on the acoustic response results of the target frequency band, the acoustic contribution results of each local region in the silencing unit structure model are determined;

[0012] Based on the pressure loss contribution result and the acoustic contribution result, overlap determination is performed on each local region in the silencing unit structure model to determine the conflict coupling zone that simultaneously meets the preset pressure loss contribution condition and the preset acoustic contribution condition;

[0013] Based on the local structural parameters corresponding to the conflict coupling zone, a region adjustment constraint is generated, and structural parameter optimization is performed according to the region adjustment constraint to generate the target optimized structural result.

[0014] Based on the above technical solution, by first generating local pressure loss distribution results and target frequency band acoustic response results, and then determining the pressure loss contribution results and acoustic contribution results corresponding to each local region, the overall pressure loss analysis and overall acoustic performance analysis can be uniformly implemented on the same local region object. This allows for same-region comparisons to be performed on local regions within the anechoic unit that simultaneously affect flow resistance performance and anechoic performance. Furthermore, by identifying and merging local regions that simultaneously meet preset pressure loss contribution conditions and preset acoustic contribution conditions to form conflict coupling zones, a clear processing object can be provided for subsequent directional optimization of local structural parameters. Then, by generating regional adjustment constraints around the conflict coupling zone and performing structural parameter optimization, the structural parameter adjustment process can be carried out around the local conflict zone.

[0015] Furthermore, methods for generating local pressure loss distribution results include:

[0016] Based on the internal flow space corresponding to the silencing unit structure model, a set of computing units is generated. According to the boundary conditions, the fluid state parameters corresponding to each computing unit are initialized and iteratively updated to obtain the effective unit pressure value corresponding to each computing unit.

[0017] The main flow direction is determined based on the spatial connection relationship between each computing unit and the effective flow velocity parameters. Segment combination is performed on multiple adjacent computing units along the main flow direction to obtain multiple location segments.

[0018] The pressure drop value of each section is determined based on the effective unit pressure value corresponding to each location section. The section identifier, spatial location of each section and the corresponding pressure drop value are then linked to generate the local pressure loss distribution results.

[0019] Furthermore, methods for determining the contribution of pressure loss include:

[0020] Based on the anechoic unit structure model, the region boundary positions are extracted, and the anechoic unit structure model is divided into regions according to the region boundary positions to obtain each local region;

[0021] Based on the results of local pressure loss distribution, the segment-region mapping relationship between each segment and each local region is determined, and based on the segment-region mapping relationship, the cumulative pressure drop value corresponding to each local region is determined.

[0022] Based on the cumulative pressure drop value corresponding to each local area, the pressure loss contribution ratio, contribution ranking result and contribution level result corresponding to each local area are determined, and pressure loss contribution result is generated.

[0023] The above methods enable the local pressure loss distribution results to be collected and quantified according to a unified local area object, forming a regionalized pressure loss analysis basis that can directly correspond to subsequent acoustic contribution results.

[0024] Furthermore, methods for generating acoustic response results for the target frequency band include:

[0025] Based on acoustic boundary conditions, the target frequency band range and entrance acoustic excitation parameters are determined;

[0026] A set of discrete frequency points is generated based on the target frequency band range, and a set of acoustic solution units is generated based on the sound-absorbing unit structure model.

[0027] The acoustic state parameters of each acoustic solution unit are initialized based on the entrance acoustic excitation parameters, and the acoustic state parameters of each acoustic solution unit are iteratively updated point by point at each discrete frequency point to obtain the effective unit sound pressure value at each discrete frequency point.

[0028] The attenuation characterization value is determined based on the effective unit sound pressure value corresponding to each discrete frequency point, and the acoustic response result of the target frequency band is generated.

[0029] Furthermore, methods for generating acoustic contribution results include:

[0030] Based on the local structural parameters corresponding to each local region, the perturbed local structural parameters corresponding to each local region are generated, and based on the perturbed local structural parameters corresponding to each local region, the perturbed noise reduction unit structure model corresponding to each local region is generated.

[0031] Based on the perturbation-induced noise reduction unit structure model corresponding to each local region, the acoustic simulation is re-executed to obtain the perturbation-induced acoustic response results of the target frequency band corresponding to each local region.

[0032] Based on the acoustic response results of the target frequency band after disturbance and the original acoustic response results of the target frequency band, the changes in acoustic response, the proportion of acoustic contribution, the ranking of contribution, and the contribution level of each local area are determined, and acoustic contribution results are generated. In this way, the changes in acoustic response of the target frequency band can be attributed to the disturbance of local structural parameters in each local area, forming a characterization result of the degree of acoustic effect for local areas, so as to perform joint analysis with the pressure loss contribution results on the same regional object.

[0033] Furthermore, methods for determining conflict coupling regions include:

[0034] Based on the pressure loss contribution results and acoustic contribution results, the joint contribution information corresponding to each local region is determined;

[0035] Based on the joint contribution information corresponding to each local region, a set of candidate pressure loss regions is determined according to the preset pressure loss contribution conditions, and a set of candidate acoustic regions is determined according to the preset acoustic contribution conditions.

[0036] Based on the candidate pressure loss region set and the candidate acoustic region set, the set of overlapping local regions is determined;

[0037] Based on the spatial connection relationship between local regions in the set of overlapping local regions, multiple overlapping local regions that meet the spatial connection conditions are merged to determine the conflict coupling zone. In this way, the spatially continuous conflict range can be identified from local regions that have both high pressure loss contribution and high acoustic contribution. This allows subsequent structural adjustments to no longer be carried out uniformly for all local regions, but to be carried out in a targeted manner around local regions with dual influence relationships.

[0038] Furthermore, the methods for generating region adjustment constraints include:

[0039] Extract local structural parameters corresponding to each conflict coupling region based on the conflict coupling region;

[0040] Based on the proportion of pressure loss contribution and acoustic contribution within the conflict coupling zone of each local structural parameter, the adjustment direction corresponding to each local structural parameter is determined.

[0041] Based on the adjustment direction and original parameter value of each local structural parameter, determine the parameter adjustment range of each local structural parameter;

[0042] By establishing a correspondence between the local structural parameters corresponding to each conflict coupling zone, the adjustment direction corresponding to each local structural parameter, and the parameter adjustment range corresponding to each local structural parameter, regional adjustment constraints are generated. In this way, the local structural parameters, adjustment direction, and parameter adjustment range corresponding to the conflict coupling zone can be associated, so that the subsequent generation process of candidate structural parameter combinations has a constraint basis oriented towards local conflict zones.

[0043] Furthermore, methods for generating the target optimization structure results include:

[0044] Candidate structural parameter combinations are generated based on region adjustment constraints, and candidate noise reduction unit structural models are generated based on the candidate structural parameter combinations.

[0045] Based on the structural models of each candidate noise reduction unit, fluid numerical simulation and acoustic simulation are performed respectively to determine the overall cumulative pressure drop value and the average attenuation value of the target frequency band corresponding to each candidate noise reduction unit structural model, and to generate performance evaluation results.

[0046] Based on the performance evaluation results, candidate noise reduction unit structure models that simultaneously meet the preset cumulative voltage drop requirements and the preset target frequency band attenuation requirements are selected, and the candidate noise reduction unit structure model ranked first is determined as the target optimized structure result. In this way, under the constraint of regional adjustment, the candidate noise reduction unit structure models can be jointly screened for pressure loss and target frequency band attenuation to form an optimized structure output result that is consistent with the conflict coupling area identification results.

[0047] Furthermore, the method for determining the preset pressure loss contribution condition and the preset acoustic contribution condition includes:

[0048] Read the pressure loss contribution ratio and acoustic contribution ratio of all local regions respectively and sort them. Determine the preset pressure loss ratio threshold and preset acoustic ratio threshold according to the preset ratio range.

[0049] Based on the preset screening ratio or preset screening quantity, determine the preset sorting intervals corresponding to the pressure loss contribution ranking results and the acoustic contribution ranking results, respectively.

[0050] Based on the pressure loss contribution level results and the acoustic contribution level results, the corresponding preset high contribution levels are determined respectively;

[0051] The following conditions are defined as the preset pressure loss contribution conditions: the pressure loss contribution ratio of the local area is greater than or equal to the preset pressure loss ratio threshold, the pressure loss contribution ranking result is within the preset ranking interval, and the pressure loss contribution level result is the preset high contribution level.

[0052] The preset acoustic contribution conditions are determined by any one of the following: the acoustic contribution ratio of a local area is greater than or equal to a preset acoustic contribution threshold, the acoustic contribution ranking result is within a preset ranking interval, or the acoustic contribution level result is a preset high contribution level.

[0053] A CFD-based conflict coupling zone identification and optimization system for exhaust mufflers includes:

[0054] The pressure loss distribution generation module is used to obtain the structural model and boundary conditions of the muffler unit of the target exhaust system under set operating conditions, and to perform fluid numerical simulation to generate local pressure loss distribution results.

[0055] The pressure loss contribution determination module determines the pressure loss contribution results for each local region in the silencing unit structure model based on the local pressure loss distribution results.

[0056] The acoustic response generation module performs acoustic simulation based on the silencing unit structure model and acoustic boundary conditions to generate acoustic response results for the target frequency band.

[0057] The acoustic contribution determination module determines the acoustic contribution results of each local region in the silencing unit structure model based on the acoustic response results of the target frequency band.

[0058] The conflict coupling zone determination module is used to perform overlap determination on each local region in the anechoic unit structure model based on the pressure loss contribution result and the acoustic contribution result, and determine the conflict coupling zone that simultaneously meets the preset pressure loss contribution condition and the preset acoustic contribution condition.

[0059] The optimization result generation module generates regional adjustment constraints based on the local structural parameters corresponding to the conflict coupling zone, and performs structural parameter optimization according to the regional adjustment constraints to generate the target optimized structural result.

[0060] Compared with related technologies, this application has the following advantages:

[0061] This application first generates local pressure loss distribution results based on fluid numerical simulation, and further determines the pressure loss contribution results corresponding to each local region; at the same time, it generates acoustic response results for the target frequency band based on acoustic simulation, and further determines the acoustic contribution results corresponding to each local region; by generating pressure loss contribution results and acoustic contribution results corresponding to each local region respectively, the pressure loss analysis and acoustic performance analysis are unified and implemented on the same set of local region objects, thereby providing a consistent processing basis for subsequent comparisons within the same region.

[0062] Based on the pressure loss contribution results and acoustic contribution results, this application performs overlap determination on each local area to identify conflict coupling areas that simultaneously meet the preset pressure loss contribution conditions and preset acoustic contribution conditions. By first identifying the conflict coupling areas, the optimization contradictions at the overall index level can be specifically located within the local space of the anechoic unit, thereby improving the pertinence of subsequent optimization analysis.

[0063] This application further generates regional adjustment constraints based on the local structural parameters corresponding to the conflict coupling zone, and performs structural parameter optimization based on the regional adjustment constraints. By establishing a correspondence between the local structural parameters in the conflict coupling zone and the corresponding adjustment direction and parameter adjustment range, the subsequent optimization process revolves around the local structural parameters that actually affect the balance between pressure loss and acoustic attenuation in the conflict zone, thereby helping to narrow the optimization search range and improve the efficiency of structural adjustment.

[0064] This application ultimately generates a target optimized structure result, which can perform constrained optimization processing around such conflict areas when local high pressure loss areas overlap with local high acoustic areas. This reduces the risk of amplifying local pressure loss to increase target frequency band attenuation or weakening key acoustic attenuation effects to reduce pressure loss. Consequently, it helps to improve the coordination and stability of the exhaust muffler unit optimization result between pressure loss control and target frequency band muffler performance. Attached Figure Description

[0065] Figure 1 A schematic diagram of the CFD conflict coupling zone identification and optimization method for an exhaust muffler unit provided in this application;

[0066] Figure 2 A data processing diagram showing the transition from the target frequency band acoustic response results to the target optimized structure results provided in this application;

[0067] Figure 3 This application provides a schematic diagram of a CFD conflict coupling zone identification and optimization system module for an exhaust muffler unit. Detailed Implementation

[0068] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0069] Example 1

[0070] Please see Figure 1-3 As shown, this embodiment provides a CFD conflict coupling region identification and optimization method for exhaust muffler units, including the following steps:

[0071] Step S10 obtains the structural model and boundary conditions of the muffler unit of the target exhaust system under the set operating conditions, and performs fluid numerical simulation to generate local pressure loss distribution results; generates local pressure loss distribution results that can characterize the pressure drop distribution state at different locations inside the muffler unit, providing input objects for subsequently determining the pressure loss contribution results corresponding to each local area in the muffler unit structural model.

[0072] In some implementations, the steps for generating the local pressure loss distribution results include:

[0073] Step S101: Obtain the muffler unit structure data corresponding to the target exhaust system under the set operating conditions; the muffler unit structure data includes at least one or more of the following: the inlet channel size, outlet channel size, cavity size, connecting channel size, transition size, expansion and contraction size, and flow guide component size of the target exhaust system; when the muffler unit includes a perforated connecting structure, it also includes one or more of the following: perforation location, perforation diameter, and perforation distribution size.

[0074] Step S102: Construct a silencing unit structure model based on the silencing unit structure data. Specifically, first, determine the inlet boundary and outlet boundary based on the inlet channel size and outlet channel size; then, generate the internal flow boundary between the inlet boundary and outlet boundary based on the cavity size, connecting channel size, transition size, expansion and contraction size, flow guiding component size, and perforation distribution size; finally, connect the inlet boundary, the outlet boundary, and the internal flow boundary to form a closed internal flow space, thus obtaining the silencing unit structure model; the silencing unit structure model includes at least three parts: the inlet boundary, the outlet boundary, and the internal flow boundary.

[0075] Step S103: Obtain the boundary conditions under the set operating conditions; the boundary conditions include at least the inlet mass flow rate, inlet temperature, and outlet static pressure; wherein, the inlet mass flow rate is used to limit the flow state of the exhaust fluid when it enters the muffler unit, the inlet temperature is used to limit the thermal state of the exhaust fluid, and the outlet static pressure is used to limit the back pressure state of the exhaust fluid when it flows out of the muffler unit; the boundary conditions can be determined based on the measured operating condition data of the target exhaust system under set speed and set load; when measured operating condition data is lacking, they can also be determined based on the design operating condition parameters of the target exhaust system.

[0076] Step S104: Generate an initial spatial unit set based on the silencing unit structure model. Specifically, taking the internal flow space corresponding to the silencing unit structure model as the processing object, firstly, perform axial segmentation on the internal flow space along the connection direction from the inlet boundary to the outlet boundary to form multiple axial continuous layers; then, perform transverse segmentation on each axial continuous layer along the cross-sectional direction to form multiple initial spatial units, and the multiple initial spatial units constitute an initial spatial unit set; wherein, each initial spatial unit includes at least a unit identifier, a unit spatial range, and a set of unit boundaries corresponding to the unit spatial range; the set of unit boundaries is used to characterize the connection boundary between the initial spatial unit and adjacent initial spatial units, and the constraint boundary between the initial spatial unit and the internal flow boundary of the silencing unit structure model.

[0077] Step S105: Based on the structural boundary change positions, perform local subdivision on the initial spatial unit set to obtain a computational unit set. Specifically, firstly, extract the channel cross-section change positions, turning positions, cavity connection positions, flow guide component positions, and perforation connection positions from the silencing unit structural model; then determine which initial spatial units' unit spatial ranges correspond to the above positions; further subdivide the initial spatial units corresponding to the above positions along the axial and transverse directions to form multiple subdivided spatial units; the initial spatial units that have not been further subdivided and the subdivided spatial units formed after further subdivision are jointly determined as the computational unit set; the computational unit set includes at least multiple unit identifiers, unit spatial ranges corresponding to each unit identifier, and unit boundary sets corresponding to each unit identifier; the computational unit set obtained through this step is used for subsequent iterative solution of fluid state parameters.

[0078] Step S106: Initialize the fluid state parameters corresponding to each computing unit based on the boundary conditions. Specifically, allocate the inlet mass flow rate to the computing units connected to the inlet boundary, allocate the outlet static pressure to the computing units connected to the outlet boundary, and assign initial temperature parameters to all computing units based on the inlet temperature. Based on this, assign initial pressure parameters and initial flow velocity parameters to each computing unit. The initial flow velocity parameters of the computing units connected to the inlet boundary are determined based on the inlet mass flow rate and inlet cross-sectional area, the initial pressure parameters of the computing units connected to the outlet boundary are determined based on the outlet static pressure, and the initial pressure parameters and initial flow velocity parameters of the remaining computing units are determined by interpolation based on the spatial relationship between the computing units connected to the inlet boundary and the computing units connected to the outlet boundary. Through the above processing, the initial fluid state parameters corresponding to each computing unit are obtained. The initial fluid state parameters include at least the initial pressure parameters and initial flow velocity parameters corresponding to each computing unit.

[0079] Step S107: Based on the initial fluid state parameters, iterative updates are performed on the fluid state parameters corresponding to each computing unit to obtain effective unit pressure values. Specifically, for each computing unit, the current pressure parameters and current flow velocity parameters of adjacent computing units sharing the unit boundary are read, and the boundary connectivity state corresponding to the shared unit boundary is read. Based on the difference between the current pressure parameters corresponding to the current computing unit and the current pressure parameters corresponding to each adjacent computing unit, the pressure correction amount transmitted to the current computing unit through each shared unit boundary is determined. Based on the component of the current flow velocity parameters corresponding to each adjacent computing unit in the normal direction of each shared unit boundary, the flow velocity correction amount transmitted to the current computing unit through each shared unit boundary is determined. The pressure correction amount is superimposed on the current pressure parameters corresponding to the current computing unit to obtain the updated pressure parameters corresponding to the current computing unit. The flow velocity correction amount is superimposed on the current flow velocity parameters corresponding to the current computing unit to obtain the updated flow velocity parameters corresponding to the current computing unit. After completing one round of updates for all computing units, the updated pressure parameter set and updated flow velocity parameter set corresponding to the current iteration are obtained.

[0080] After completing one round of updates for all computational units, for each computational unit, the updated pressure parameters in the current iteration and the pressure parameters in the previous iteration are extracted, and the absolute value of the difference between the two is calculated to obtain the pressure parameter change for that computational unit. The pressure parameter changes for all computational units are combined into a pressure change set. When the maximum change in the pressure change set is less than the set convergence condition, the updated pressure parameter set for the current iteration is determined as a valid solution. When the maximum change in the pressure change set is greater than or equal to the set convergence condition, the updated pressure parameter set and the updated flow velocity parameter set for the current iteration are determined as the input parameter set for the next iteration.

[0081] In this step, the effective unit pressure value includes at least the average pressure value corresponding to each calculation unit; when it is necessary to improve the accuracy of subsequent section pressure drop calculation, the average pressure value at the inlet side and the average pressure value at the outlet side of each calculation unit along the main flow direction are further determined.

[0082] Step S108: Determine the main flow direction based on the spatial connection relationship between each computing unit and the effective flow velocity parameters. Specifically, first, read the set of computing units connected to the inlet boundary and the set of computing units connected to the outlet boundary; then, starting from the set of computing units connected to the inlet boundary, search step by step to the set of computing units connected to the outlet boundary according to the unit boundary connection relationship between each computing unit and the direction of the effective flow velocity parameters corresponding to each computing unit, to obtain the main flow path from the inlet boundary to the outlet boundary; determine the overall direction corresponding to the main flow path as the main flow direction. Through this step, the unified direction on which subsequent segment division and segment start and end pressure extraction are based is clarified.

[0083] Step S109: Perform segment combination on multiple adjacent computing units along the main flow direction to obtain multiple position segments. Specifically, according to the order of each computing unit in the main flow path, read a preset number of computing units consecutively and combine the preset number of computing units read into a position segment. When the computing unit corresponding to the end of the segment shares the unit boundary with the computing unit corresponding to the beginning of the next segment, it is determined that the two position segments are spatially continuous. For each position segment, assign a unique segment identifier and record the set of computing unit identifiers within the segment, the segment start position, and the segment end position corresponding to that position segment.

[0084] Step S110: Determine the pressure drop value of each location segment based on the effective unit pressure value corresponding to each location segment. Specifically, for each location segment, extract the pressure value of the first calculation unit in the location segment along the main flow direction in the inlet side as the segment start-end pressure value, and extract the pressure value of the last calculation unit in the location segment along the main flow direction in the outlet side as the segment end pressure value. When a location segment contains only one calculation unit, extract the pressure value of the calculation unit along the main flow direction in the inlet side as the segment start-end pressure value, and extract the pressure value of the calculation unit along the main flow direction in the outlet side as the segment end pressure value. Subsequently, calculate the difference between the segment start-end pressure value and the segment end pressure value to obtain the segment pressure drop value corresponding to that location segment.

[0085] Step S111: Establish a one-to-one correspondence between the segment identifier, the set of calculation unit identifiers within the segment, the segment start position, the segment end position, and the corresponding segment pressure drop value for each location segment, and arrange them in order according to the main flow direction to generate the local pressure loss distribution result.

[0086] The local pressure loss distribution result includes at least multiple segment identifiers arranged in the main flow direction and the segment pressure drop value corresponding to each segment identifier; in a preferred embodiment, it further includes the set of calculation unit identifiers within each segment, the segment start position, and the segment end position. Through steps S104 to S111, the process of performing fluid numerical simulation on the silencing unit structure model and boundary conditions and generating the local pressure loss distribution result is completed.

[0087] In some implementations, to illustrate the iterative update process of the fluid state parameters corresponding to each computing unit, for example:

[0088] A certain silencing unit is divided into four adjacent computing units along the main flow direction, denoted as computing unit A1, computing unit A2, computing unit A3, and computing unit A4. At the start of the current iteration, the current pressure parameters corresponding to computing units A1 to A4 are 108.0 kPa, 106.5 kPa, 104.8 kPa, and 103.9 kPa, respectively, and the corresponding current flow velocity parameters are 18.0 m / s, 20.5 m / s, 22.0 m / s, and 21.2 m / s, respectively. Taking computing unit A2 as the current processing object, the current pressure parameters corresponding to computing units A1 and A3, which share the unit boundary with computing unit A2, are read. The pressure differences relative to computing unit A2 are found to be 1.5 kPa and -1.7 kPa, respectively. Combining this with the boundary connectivity state corresponding to the shared unit boundary, the pressure correction amount transmitted to computing unit A2 is determined to be 0.3 kPa. At the same time, the pressure parameters corresponding to the shared unit boundary are read from computing units A1 and A3. The component of the current flow velocity parameter in the normal direction of the shared unit boundary is used to determine the flow velocity correction amount to be transferred to computing unit A2 as 0.4 m / s. Therefore, the current pressure parameter of 106.5 kPa corresponding to computing unit A2 is superimposed with the pressure correction amount to obtain the updated pressure parameter of 106.8 kPa. The current flow velocity parameter of 20.5 m / s corresponding to computing unit A2 is superimposed with the flow velocity correction amount to obtain the updated flow velocity parameter of 20.9 m / s. After completing one round of updates for all computing units, if the maximum value of the pressure parameter change corresponding to each computing unit in this round is 0.06 kPa, and the upper limit of pressure change corresponding to the convergence condition is set to 0.05 kPa, then the set of updated pressure parameters in this round is used as the input for the next round of iteration. If the maximum pressure change decreases to 0.03 kPa after the next round of iteration, then the set of updated pressure parameters in this round is determined as a valid solution result, and the average pressure value corresponding to each computing unit is determined as the valid unit pressure value.

[0089] Step S20: Based on the local pressure loss distribution results, determine the pressure loss contribution results corresponding to each local region in the anechoic unit structure model; apply the local pressure loss distribution results to a unified local region object in the anechoic unit structure model to generate the pressure loss contribution results corresponding to each local region, providing input objects for subsequent comparison and overlap determination with the acoustic contribution results in the same region.

[0090] In some implementations, the steps for determining the pressure loss contribution include:

[0091] Step S201: Extract the region boundary positions based on the silencing unit structure model; the region boundary positions include at least one or more of the following: channel cross-section change position, turning transition position, cavity connection position, flow guide component start and end position, and perforation connection position; wherein, the channel cross-section change position is used to characterize the position where the cross-sectional size of the flow space changes, the turning transition position is used to characterize the position where the flow direction changes, the cavity connection position is used to characterize the position where different cavities are connected, the flow guide component start and end position is used to characterize the starting and ending positions of the flow guide component's range of action, and the perforation connection position is used to characterize the location of the perforation connection structure.

[0092] Step S202: Based on the regional boundary positions, the anechoic unit structure model is divided into regions to obtain local regions in the anechoic unit structure model. Specifically, according to the main flow direction, the continuous spatial range between any two adjacent regional boundary positions is determined as a local region, and each local region is assigned a unique region identifier. Each local region includes at least a region identifier and the regional spatial range corresponding to the region identifier. The local regions formed by this step serve as the unified object for subsequent pressure loss contribution analysis and acoustic contribution analysis.

[0093] Step S203: Based on the local pressure loss distribution results, determine the segment-region mapping relationship between each segment identifier and each local region. Specifically, read the segment start position, segment end position, and segment pressure drop value corresponding to each segment identifier, and read the regional spatial range corresponding to each local region; determine which local region's regional spatial range each segment identifier's segment start position and segment end position fall into; when the segment start position and segment end position of a certain segment both fall into the same local region, establish a one-to-one relationship between the segment identifier and the region identifier of that local region. The mapping relationship is established, and the segment pressure drop value corresponding to the segment is determined as the segment-assigned pressure drop value corresponding to the local area. When the starting position and ending position of a segment fall into two adjacent local areas respectively, the segment pressure drop value corresponding to the segment is allocated according to the length ratio of the segment in the two adjacent local areas, so as to obtain the segment allocation pressure drop value corresponding to the two adjacent local areas respectively, and a one-to-many mapping relationship is established between the segment identifier and the area identifier of the two adjacent local areas respectively. Through the above processing, the segment-area mapping relationship between each segment identifier and each local area is obtained.

[0094] Furthermore, to illustrate the segment-region mapping relationship and the segment voltage drop allocation process, for example:

[0095] Three location segments are obtained along the main flow direction: segment B1, segment B2, and segment B3. The corresponding starting and ending positions of these segments are 0 mm to 40 mm, 40 mm to 90 mm, and 90 mm to 130 mm, respectively, and the corresponding pressure drop values ​​are 0.8 kPa, 1.5 kPa, and 0.7 kPa, respectively. At the same time, the silencing unit structure model is divided into local regions C1, C2, and C3 according to the regional boundary positions. Local region C1 corresponds to 0 mm to 50 mm, local region C2 corresponds to 50 mm to 100 mm, and local region C3 corresponds to 100 mm to 130 mm. Therefore, segment B1 falls entirely within local region C1. Thus, a one-to-one mapping relationship is established between segment B1 and local region C1, and 0.8 kPa is determined as the segment's assigned pressure drop value for local region C1. Segment B2 spans both local regions C1 and C2, with a length of 10 mm within local region C1 and 40 mm within local region C2. Therefore, a 1.5 kPa allocation is performed according to a 1:4 length ratio, resulting in a segment-assigned pressure drop value of 0.3 kPa for local region C1 and 1.2 kPa for local region C2. Segment B3 spans both local regions C2 and C3, with a length of 10 mm within local region C2 and 30 mm within local region C3. Therefore, a 1:3 length allocation is performed on 0.7 kPa, resulting in a segment-assigned pressure drop value of 0.175 kPa for local region C2 and 0.525 kPa for local region C3. Based on the above mapping relationship, the cumulative pressure drop value corresponding to local region C1 is 1.1 kPa, the cumulative pressure drop value corresponding to local region C2 is 1.375 kPa, and the cumulative pressure drop value corresponding to local region C3 is 0.525 kPa.

[0096] Step S204: Based on the segment-region mapping relationship, determine the cumulative pressure drop value corresponding to each local region. Specifically, read all segment-assigned pressure drop values ​​and segment-allocated pressure drop values ​​corresponding to each local region, and accumulate all segment-assigned pressure drop values ​​and segment-allocated pressure drop values ​​corresponding to the same local region to obtain the cumulative pressure drop value corresponding to that local region. The cumulative pressure drop value is used to characterize the local effect intensity of that local region on the overall pressure loss. Through the above processing, the cumulative pressure drop value corresponding to each local region is obtained.

[0097] Step S205: Determine the pressure loss contribution ratio of each local area based on the cumulative pressure drop value of each local area. Specifically, read the cumulative pressure drop value of all local areas and sum the cumulative pressure drop values ​​of all local areas to obtain the overall cumulative pressure drop value; then divide the cumulative pressure drop value of each local area by the overall cumulative pressure drop value to obtain the pressure loss contribution ratio of that local area; through the above processing, the pressure loss contribution ratio of each local area is obtained.

[0098] Step S206: Based on the pressure loss contribution ratio of each local area, determine the contribution ranking and contribution level results of each local area. Specifically, read the pressure loss contribution ratio of each local area and sort the local areas from largest to smallest according to the pressure loss contribution ratio to obtain the contribution ranking results of each local area; then, based on the distribution of the pressure loss contribution ratio, divide each local area into high pressure loss contribution area, medium pressure loss contribution area, and low pressure loss contribution area to obtain the contribution level results of each local area; through the above processing, obtain the contribution ranking and contribution level results of each local area.

[0099] Step S207 generates a pressure loss contribution result based on the cumulative pressure drop value, pressure loss contribution ratio, contribution ranking result, and contribution level result corresponding to each local region. Specifically, for each local region, the region identifier, cumulative pressure drop value, pressure loss contribution ratio, contribution ranking result, and contribution level result corresponding to that local region are read, and a correspondence is established between the above contents to generate a pressure loss contribution result; the pressure loss contribution result includes at least the region identifier, cumulative pressure drop value, and pressure loss contribution ratio corresponding to each local region; in a preferred embodiment, it further includes the contribution ranking result and contribution level result. Through steps S203 to S207, the subsequent processing of determining the pressure loss contribution result corresponding to each local region in the anechoic unit structure model based on the local pressure loss distribution result is completed. The pressure loss contribution result is called when performing the same region overlap determination as the acoustic contribution result.

[0100] Step S30: Perform acoustic simulation based on the anechoic unit structure model and acoustic boundary conditions to generate acoustic response results for the target frequency band; based on the anechoic unit structure model and acoustic boundary conditions, generate acoustic response results for the target frequency band that can characterize the attenuation capability of the anechoic unit in the target frequency band, providing input objects for subsequent determination of the acoustic contribution results corresponding to each local region.

[0101] In some implementations, the steps for generating the acoustic response results for the target frequency band include:

[0102] Step S301: Obtain acoustic boundary conditions and determine the target frequency band range and inlet acoustic excitation parameters. Specifically, read the measured noise spectrum data of the target exhaust system under set operating conditions. The measured noise spectrum data includes at least multiple frequency points and the sound pressure amplitude corresponding to each frequency point. Perform continuous scanning on the sound pressure amplitude corresponding to adjacent frequency points in ascending order of frequency value. When the sound pressure amplitude corresponding to multiple consecutive frequency points is greater than or equal to the preset reference sound pressure amplitude, determine the starting frequency value and ending frequency value of the multiple consecutive frequency points as the target frequency band range. When there are multiple frequency intervals that meet the conditions, determine the frequency interval with the largest cumulative sound pressure amplitude value as the target frequency band range.

[0103] When measured noise spectrum data is unavailable, the fundamental frequency and all harmonic frequencies of the target exhaust system under the set operating conditions are read, and the interval from the fundamental frequency to the highest harmonic frequency is determined as the target frequency band range. After determining the target frequency band range, the measured inlet sound pressure data of the target exhaust system under the set operating conditions are read, and the inlet sound pressure amplitude corresponding to the target frequency band range is extracted and determined as the inlet acoustic excitation parameter. When measured inlet sound pressure data is unavailable, the preset standard inlet sound pressure value under the design operating conditions is read and determined as the inlet acoustic excitation parameter.

[0104] In some implementations, the preset reference sound pressure amplitude is determined based on the noise spectrum distribution of the target exhaust system under set operating conditions. Specifically, firstly, the measured noise spectrum data of the target exhaust system under set operating conditions is read, and the sound pressure amplitude corresponding to all frequency points is extracted; then, statistical processing is performed on the sound pressure amplitude corresponding to all frequency points to obtain one or more of the average sound pressure amplitude, median sound pressure amplitude, or high-frequency occurrence value; subsequently, a statistical value is selected from the average sound pressure amplitude, median sound pressure amplitude, or high-frequency occurrence value as a reference value, and a preset margin is added to the reference value to obtain the preset reference sound pressure amplitude. The preset reference sound pressure amplitude determined in this way is used as a criterion for screening the target frequency band range, so that the subsequently obtained target frequency band range corresponds to the frequency interval where the sound pressure amplitude is relatively prominent; when measured noise spectrum data is lacking, the preset reference sound pressure amplitude can also be determined based on the historical noise spectrum statistical results of the target exhaust system under the same type of operating conditions.

[0105] Step S302: Generate a discrete frequency point set based on the target frequency band range. Specifically, read the starting frequency value and the ending frequency value of the target frequency band range and set a frequency step size; take the starting frequency value as the first discrete frequency value, and continuously add the frequency step size to the previous discrete frequency value until multiple discrete frequency values ​​are obtained that are less than or equal to the ending frequency value; when the last discrete frequency value is less than the ending frequency value, add the ending frequency value to the multiple discrete frequency values; then assign a unique frequency point identifier to each discrete frequency value in ascending order of frequency value to form a discrete frequency point set; the discrete frequency point set includes at least multiple frequency point identifiers and frequency values ​​corresponding to each frequency point identifier.

[0106] In some implementations, to illustrate the process of determining the target frequency band range and the set of discrete frequency points, for example:

[0107] In the measured noise spectrum data of the target exhaust system under set operating conditions, the sound pressure amplitudes at 100 Hz, 150 Hz, 200 Hz, 250 Hz, 300 Hz, 350 Hz, and 400 Hz are 72 dB, 78 dB, 83 dB, 85 dB, 84 dB, 79 dB, and 73 dB, respectively. After statistical processing of the sound pressure amplitudes at all frequency points, the average sound pressure amplitude is obtained as 79.1 dB. A preset margin is added to this average sound pressure amplitude to determine a preset reference sound pressure amplitude of 82 dB. Subsequently, a continuous scan of the sound pressure amplitudes at adjacent frequency points is performed to determine the values ​​at 200 Hz, 250 Hz, and 400 Hz. The sound pressure amplitude corresponding to 300 Hz is greater than or equal to 82 dB. Therefore, the range of 200 Hz to 300 Hz is determined as the target frequency band. Furthermore, when the frequency step size is set to 25 Hz, a discrete frequency point set can be generated based on 200 Hz to 300 Hz. The discrete frequency point set includes 200 Hz, 225 Hz, 250 Hz, 275 Hz, and 300 Hz. After performing acoustic solutions on the above discrete frequency points, if the corresponding attenuation values ​​are 9.8 dB, 10.6 dB, 11.4 dB, 10.9 dB, and 10.1 dB, respectively, then the average attenuation value of the target frequency band can be further obtained as 10.56 dB.

[0108] Step S303: Generate an acoustic solution unit set based on the anechoic unit structure model. Specifically, taking the internal sound propagation space corresponding to the anechoic unit structure model as the processing object, first perform axial segmentation along the connection direction from the inlet boundary to the outlet boundary to obtain multiple axial continuous layers; then perform transverse segmentation on each axial continuous layer along the cross-sectional direction to form multiple initial acoustic space units; wherein, each initial acoustic space unit includes at least a unit identifier, a unit space range, and a set of unit boundaries corresponding to the unit space range.

[0109] Subsequently, the channel cross-section change positions, turning positions, cavity connection positions, flow guide component positions, and perforation connection positions are extracted from the anechoic unit structure model; it is determined which initial acoustic space units have unit space ranges corresponding to the above positions; the initial acoustic space units corresponding to the above positions are further subdivided along the axial and lateral directions to form multiple subdivided acoustic space units; the initial acoustic space units that have not been further subdivided and the subdivided acoustic space units formed after further subdivision are jointly determined as the acoustic solution unit set; the acoustic solution unit set includes at least multiple unit identifiers, unit space ranges corresponding to each unit identifier, and unit boundary sets corresponding to each unit identifier.

[0110] Step S304: Initialize the acoustic state parameters corresponding to each acoustic solution unit based on the entrance acoustic excitation parameters. Specifically, assign the entrance sound pressure amplitude to the acoustic solution unit connected to the entrance boundary, and determine it as the initial sound pressure parameter corresponding to the acoustic solution unit connected to the entrance boundary. When the entrance acoustic excitation parameters also include entrance phase parameters, assign the entrance phase parameters to the acoustic solution unit connected to the entrance boundary, and determine it as the initial phase parameter corresponding to the acoustic solution unit connected to the entrance boundary.

[0111] For the remaining acoustic solution units not connected to the entrance boundary, first extract the spatial distance along the main propagation direction between the center position of the acoustic solution unit and the center position of the acoustic solution unit connected to the entrance boundary, and determine the spatial distance as the propagation distance; then read the total propagation distance along the main propagation direction between the entrance boundary and the exit boundary; divide the propagation distance by the total propagation distance to obtain the distance ratio value corresponding to the acoustic solution unit; then multiply the distance ratio value by the entrance sound pressure amplitude to obtain the sound pressure attenuation amount corresponding to the acoustic solution unit; subtract the sound pressure attenuation amount from the entrance sound pressure amplitude to obtain the initial sound pressure parameters corresponding to the acoustic solution unit.

[0112] When the entrance acoustic excitation parameters also include entrance phase parameters, the center frequency value within the target frequency band is read, and based on the center frequency value and the total propagation distance, a preset total phase change between the entrance boundary and the exit boundary is determined; then, the distance ratio value is multiplied by the preset total phase change to obtain the phase change corresponding to the acoustic solving unit; the entrance phase parameters are added to the phase change to obtain the initial phase parameters corresponding to the acoustic solving unit.

[0113] This step yields the initial acoustic state parameters corresponding to each acoustic solution unit; the initial acoustic state parameters include at least the initial sound pressure parameters corresponding to each acoustic solution unit; when the inlet acoustic excitation parameters include the inlet phase parameters, they also include the initial phase parameters corresponding to each acoustic solution unit.

[0114] Step S305: At each discrete frequency point, perform point-by-point iterative updates on the acoustic state parameters corresponding to each acoustic solution unit to obtain the effective unit sound pressure value corresponding to each discrete frequency point. Specifically, for each discrete frequency point, read the frequency value corresponding to that discrete frequency point, and determine the initial acoustic state parameters corresponding to each acoustic solution unit as the initial input parameter set at that discrete frequency point.

[0115] Subsequently, for each acoustic solving unit, the current sound pressure parameters of the adjacent acoustic solving units sharing the unit boundary with this acoustic solving unit are read, and the boundary connectivity state corresponding to the shared unit boundary is read; based on the difference between the current sound pressure parameters of the current acoustic solving unit and the current sound pressure parameters of each adjacent acoustic solving unit, the sound pressure correction amount transmitted to the current acoustic solving unit through each shared unit boundary is determined; the sound pressure correction amount is superimposed on the current sound pressure parameters of the current acoustic solving unit to obtain the updated sound pressure parameters corresponding to the acoustic solving unit.

[0116] After completing one round of updates for all acoustic solution units, for each acoustic solution unit, the updated sound pressure parameters in the current iteration and the sound pressure parameters in the previous iteration are extracted, and the absolute value of the difference between the two is calculated to obtain the change in sound pressure parameters corresponding to that acoustic solution unit. The change in sound pressure parameters corresponding to all acoustic solution units is formed into a set of sound pressure change values. When the maximum change value in the set of sound pressure change values ​​is less than the set acoustic convergence condition, the updated sound pressure parameter set corresponding to the current iteration is determined as the effective unit sound pressure value at that discrete frequency point. When the maximum change value in the set of sound pressure change values ​​is greater than or equal to the set acoustic convergence condition, the updated sound pressure parameter set corresponding to the current iteration is used as the input for the next iteration, and the iterative update continues.

[0117] In some implementations, the sound pressure correction is formed based on the boundary sound pressure difference between the current acoustic solving unit and its adjacent acoustic solving units. Specifically, for each acoustic solving unit, the current sound pressure parameter corresponding to that acoustic solving unit is first read, and the current sound pressure parameters corresponding to each adjacent acoustic solving unit sharing the unit boundary are also read; then, the sound pressure difference between the current acoustic solving unit and each adjacent acoustic solving unit is calculated respectively; subsequently, based on the boundary length, boundary direction, or boundary connectivity state corresponding to each shared unit boundary, each sound pressure difference is assigned... The corresponding boundary correction weights are then calculated. Each sound pressure difference is multiplied by its corresponding boundary correction weight to obtain the boundary correction component transmitted to the current acoustic solution unit via the boundaries of each shared unit. Finally, all boundary correction components are summed to obtain the sound pressure correction amount corresponding to the current acoustic solution unit. In this way, the sound pressure correction amount reflects both the sound pressure difference between the current acoustic solution unit and adjacent acoustic solution units, and the difference in the effect of different shared unit boundaries on sound pressure transmission. This allows the updated sound pressure parameters to more accurately characterize the sound pressure transmission process between units.

[0118] Step S306: Determine the input sound pressure value and output sound pressure value corresponding to each discrete frequency point based on the effective unit sound pressure value corresponding to each discrete frequency point; specifically, for each discrete frequency point, extract the effective unit sound pressure value corresponding to all acoustic solution units connected to the entrance boundary, and perform averaging processing on the all effective unit sound pressure values ​​to obtain the input sound pressure value corresponding to the discrete frequency point; extract the effective unit sound pressure value corresponding to all acoustic solution units connected to the exit boundary, and perform averaging processing on the all effective unit sound pressure values ​​to obtain the output sound pressure value corresponding to the discrete frequency point.

[0119] This step yields the input and output sound pressure levels for each discrete frequency point.

[0120] Step S307: Determine the attenuation characterization value corresponding to each discrete frequency point based on the input sound pressure value and the output sound pressure value. Specifically, for each discrete frequency point, first calculate the difference between the input sound pressure value and the output sound pressure value to obtain the basic attenuation value corresponding to that discrete frequency point; when using the transmission loss characterization method, convert the basic attenuation value into a transmission loss value based on the ratio between the input sound pressure value and the output sound pressure value; when using the insertion loss characterization method, convert the basic attenuation value into an insertion loss value; in this embodiment, it is preferable to determine the transmission loss value corresponding to each discrete frequency point as the attenuation characterization value.

[0121] Step S308: Establish a one-to-one correspondence between each discrete frequency point identifier and the corresponding attenuation characterization value to generate the target frequency band acoustic response result; specifically, arrange each discrete frequency point identifier in ascending order of discrete frequency value, and bind each discrete frequency point identifier with the corresponding attenuation characterization value to form the target frequency band acoustic response result; the target frequency band acoustic response result includes at least multiple frequency point identifiers and the attenuation characterization value corresponding to each frequency point identifier.

[0122] Step S309: Determine the average attenuation value of the target frequency band based on the acoustic response result of the target frequency band, and incorporate the average attenuation value of the target frequency band into the acoustic response result of the target frequency band; specifically, read the attenuation characterization values ​​corresponding to all discrete frequency points in the acoustic response result of the target frequency band, and average all attenuation characterization values ​​to obtain the average attenuation value of the target frequency band; when it is necessary to identify the peak attenuation position, extract the maximum and minimum values ​​among all attenuation characterization values ​​to obtain the maximum attenuation value and minimum attenuation value of the frequency band, respectively, and incorporate the average attenuation value, maximum attenuation value, and minimum attenuation value of the target frequency band into the acoustic response result of the target frequency band.

[0123] Through steps S301 to S309, the process of performing acoustic simulation based on the silencing unit structure model and acoustic boundary conditions to generate acoustic response results for the target frequency band is completed.

[0124] Step S40: Based on the acoustic response results of the target frequency band, determine the acoustic contribution results corresponding to each local region in the anechoic unit structure model; apply the acoustic response results of the target frequency band to each local region in the anechoic unit structure model, determine the degree of effect of each local region on the acoustic attenuation of the target frequency band, and generate acoustic contribution results that can be compared and overlapped with the pressure loss contribution results in the same region.

[0125] In some implementations, the steps for determining the acoustic contribution result include:

[0126] Step S401: Read the acoustic response results of the target frequency band and the local region identification system formed in step S20; specifically, read the region identification and spatial range corresponding to each local region, and read the acoustic response results of the target frequency band formed in step S30; since the acoustic simulation in step S30 uses the local region identification system formed in step S20, the current step directly uses each local region as a unified analysis object without re-dividing the regions; through this step, a set of acoustic contribution analysis objects is obtained.

[0127] Step S402: Extract local structural parameters corresponding to each local region based on the silencing unit structure model. Specifically, for each local region, read the boundary data within the spatial range of the corresponding local region, and extract one or more of the following parameters based on the boundary data: local channel width parameter, local channel height parameter, local cavity length parameter, local cavity width parameter, local turning angle parameter, local guide component length parameter, and local perforation diameter parameter, as the local structural parameters corresponding to the local region.

[0128] Step S403: Generate perturbed local structural parameters for each local region based on the local structural parameters corresponding to each local region. Specifically, for the current local region, select a type of local structural parameters corresponding to the local region as the current perturbation object, and apply a parameter perturbation of a preset amplitude to the current perturbation object, while keeping the local structural parameters corresponding to other local regions unchanged.

[0129] When the current disturbance object is a local channel width parameter or a local channel height parameter, a preset increment value is added or a preset decrement value is reduced based on the original parameter value; when the current disturbance object is a local cavity length parameter or a local cavity width parameter, a preset expansion amount is added or a preset shrinkage amount is reduced based on the original parameter value; when the current disturbance object is a local turning angle parameter, a local guide component length parameter, or a local perforation diameter parameter, a corresponding preset change amount is added or reduced based on the original parameter value, respectively; the preset amplitude is determined proportionally based on the original parameter value corresponding to the current disturbance object; through this step, the disturbed local structural parameters corresponding to each local area are obtained.

[0130] In some implementations, the preset amplitude is determined proportionally based on the original parameter value corresponding to the current disturbance object. Specifically, the original parameter value corresponding to the current disturbance object is first read, and a disturbance ratio corresponding to the type of disturbance object is determined. When the current disturbance object is a local channel width parameter, local channel height parameter, local cavity length parameter, or local cavity width parameter, the disturbance ratio is determined based on the allowable variation range of that type of size parameter. When the current disturbance object is a local turning angle parameter, local guide member length parameter, or local perforation diameter parameter, the disturbance ratio is determined based on the processing adjustment range or design variation range of that type of structural parameter. Subsequently, the original parameter value is multiplied by the disturbance ratio to obtain the corresponding preset amplitude. The preset amplitude determined in this way can change synchronously with the magnitude of the original parameter value of the current disturbance object, avoiding excessive disturbance to local structures with small parameter values ​​or excessive disturbance to local structures with large parameter values. This ensures that subsequent disturbances to local structural parameters can cause identifiable acoustic response changes without deviating from the reasonable variation range of the current local structural parameters.

[0131] Step S404: Generate a disturbance-induced noise reduction unit structure model for each local region based on the disturbance-induced local structural parameters corresponding to each local region. Specifically, for each local region, replace the original local structural parameters corresponding to that local region in the original noise reduction unit structure model with the disturbance-induced local structural parameters corresponding to that local region, while keeping the original structural parameters corresponding to other local regions unchanged, to obtain the disturbance-induced noise reduction unit structure model corresponding to the current local region.

[0132] Step S405: Based on the perturbation-induced noise reduction unit structure model corresponding to each local region, re-execute the acoustic response solution corresponding to step S30 to obtain the perturbation-induced target frequency band acoustic response results corresponding to each local region. Specifically, keep the target frequency band range, entrance acoustic excitation parameters, discrete frequency point set and acoustic solution unit generation rules unchanged in step S30, only replace the acoustic solution object with the perturbation-induced noise reduction unit structure model corresponding to the current local region, and re-execute steps S304 to S309 to obtain the perturbation-induced target frequency band acoustic response results corresponding to the current local region.

[0133] Step S406: Based on the acoustic response results of the target frequency band after disturbance and the acoustic response results of the original target frequency band, determine the acoustic response change amount corresponding to each local region. Specifically, for each local region, read the average attenuation value of the target frequency band in the acoustic response results of the original target frequency band and read the average attenuation value of the target frequency band in the acoustic response results of the target frequency band after disturbance corresponding to that local region, calculate the difference between the two, and obtain the average attenuation change amount corresponding to that local region. When it is necessary to improve the evaluation accuracy, also read the attenuation characterization value corresponding to each discrete frequency point in the acoustic response results of the original target frequency band and the attenuation characterization value corresponding to each discrete frequency point in the acoustic response results of the target frequency band after disturbance, calculate the difference point by point according to the same frequency point identifier, and sum or average the differences corresponding to all discrete frequency points to obtain the comprehensive frequency change amount corresponding to that local region.

[0134] The change in acoustic response includes at least the change in average attenuation; in a preferred embodiment, it further includes the overall change in frequency points.

[0135] As another example, to illustrate the process of analyzing the perturbation of local structural parameters and their acoustic contribution, for example:

[0136] Assume the original value of the local channel width parameter corresponding to local region D2 is 42 mm, and the original value of the local cavity length parameter corresponding to local region D3 is 96 mm. For local region D2, if the perturbation ratio is determined to be 5% based on the allowable variation range of the size parameters, the corresponding preset amplitude is 2.1 mm, and the perturbed local channel width parameter is 44.1 mm based on the original parameter value. For local region D3, if the perturbation ratio is determined to be 4% based on the allowable variation range of the size parameters, the corresponding preset amplitude is 3.84 mm, and the perturbed local cavity length parameter is 99.84 mm based on the original parameter value. While keeping the original structural parameters of the other local regions unchanged, the perturbed anechoic unit structural models are generated and the acoustic simulation is re-executed. If the original target frequency band average attenuation is 10.56 dB, then the perturbated target frequency band average attenuation in local region D2 is 10.12 dB, resulting in an average attenuation change of -0.44 dB for this local region. Similarly, the perturbated target frequency band average attenuation in local region D3 is 9.86 dB, resulting in an average attenuation change of -0.70 dB for this local region. Summing the average attenuation changes across all local regions, assuming an overall average attenuation change of 2.20 dB, the acoustic contribution percentage of local region D2 is 0.44 divided by 2.20, and the acoustic contribution percentage of local region D3 is 0.70 divided by 2.20, yielding 20% ​​and 31.8% respectively. Therefore, local region D3 has a greater impact on the acoustic attenuation of the target frequency band than local region D2, and local region D3 can be preferentially identified as a high acoustic contribution region.

[0137] Step S407: Summarize the acoustic response changes corresponding to all local regions to obtain a set of acoustic response changes corresponding to each local region. Specifically, establish a correspondence between the region identifiers corresponding to each local region and the acoustic response changes corresponding to each local region to form a set of acoustic response changes. The set of acoustic response changes includes at least multiple region identifiers and acoustic response changes corresponding to each region identifier.

[0138] Step S408: Based on the set of acoustic response changes, determine the acoustic contribution ratio of each local region. Specifically, read the average attenuation change of all local regions and sum the average attenuation changes of all local regions to obtain the overall average attenuation change; then divide the average attenuation change of each local region by the overall average attenuation change to obtain the acoustic contribution ratio of that local region; when using the frequency point comprehensive change, normalize the average attenuation change and the frequency point comprehensive change of each local region respectively, and then average the two to obtain the comprehensive acoustic contribution ratio of that local region.

[0139] Step S409: Based on the acoustic contribution ratio of each local region, determine the contribution ranking result and contribution level result of each local region. Specifically, sort each local region from largest to smallest according to the acoustic contribution ratio to obtain the contribution ranking result; then, based on the distribution of the acoustic contribution ratio, divide each local region into high acoustic contribution region, medium acoustic contribution region and low acoustic contribution region to obtain the contribution level result.

[0140] Step S410: Generate acoustic contribution results based on the acoustic response change, acoustic contribution ratio, contribution ranking results, and contribution level results corresponding to each local region.

[0141] Specifically, for each local area, the corresponding area identifier, acoustic response change, acoustic contribution ratio, contribution ranking result, and contribution level result are read, and the above contents are established to generate an acoustic contribution result; the acoustic contribution result includes at least the area identifier, acoustic response change, and acoustic contribution ratio corresponding to each local area; in a preferred embodiment, it further includes the contribution ranking result and contribution level result.

[0142] Through steps S401 to S410, the process of determining the acoustic contribution results corresponding to each local region in the anechoic unit structure model based on the acoustic response results of the target frequency band is completed; the acoustic contribution results are used in step S50.

[0143] Step S50: Based on the pressure loss contribution result and the acoustic contribution result, perform overlap determination on each local region in the anechoic unit structure model to determine the conflict coupling region that simultaneously meets the preset pressure loss contribution condition and the preset acoustic contribution condition; map the pressure loss contribution result and the acoustic contribution result onto the same set of local region objects, perform dual-condition filtering and spatial continuity merging on each local region to generate the conflict coupling region, and provide input objects for subsequent generation of region adjustment constraints based on the local structural parameters corresponding to the conflict coupling region.

[0144] In some implementations, the preset pressure loss contribution condition includes any one of the following: the pressure loss contribution ratio of the local area is greater than or equal to a preset pressure loss ratio threshold, the pressure loss contribution ranking result of the local area is within a preset ranking interval, or the pressure loss contribution level result of the local area is a preset high contribution level; the preset acoustic contribution condition includes any one of the following: the acoustic contribution ratio of the local area is greater than or equal to a preset acoustic ratio threshold, the acoustic contribution ranking result of the local area is within a preset ranking interval, or the acoustic contribution level result of the local area is a preset high contribution level.

[0145] In some implementations, the steps for determining the conflict coupling region include:

[0146] Step S501: Based on the pressure loss contribution result and the acoustic contribution result, determine the joint contribution information corresponding to each local area. Specifically, for each local area, read the area identifier, area spatial range, area cumulative pressure drop value, pressure loss contribution ratio, pressure loss contribution ranking result, pressure loss contribution level result, acoustic response change, acoustic contribution ratio, acoustic contribution ranking result, and acoustic contribution level result corresponding to that local area; then establish a one-to-one correspondence between the above contents belonging to the same area identifier to obtain the joint contribution information corresponding to that local area; the joint contribution information includes at least the area identifier, pressure loss contribution ratio, and acoustic contribution ratio corresponding to that local area, and in a preferred embodiment, further includes the area cumulative pressure drop value, pressure loss contribution ranking result, pressure loss contribution level result, acoustic response change, acoustic contribution ranking result, and acoustic contribution level result.

[0147] Step S502: Determine the candidate pressure loss region set based on the joint contribution information corresponding to each local region. Specifically, for each local region, read the pressure loss contribution ratio, pressure loss contribution ranking result, and pressure loss contribution level result corresponding to that local region. First, compare the pressure loss contribution ratio corresponding to that local region with a preset pressure loss ratio threshold. When the pressure loss contribution ratio corresponding to that local region is greater than or equal to the preset pressure loss ratio threshold, include that local region in the candidate pressure loss region set. When the pressure loss contribution ratio corresponding to that local region is less than the preset pressure loss ratio threshold, further determine whether the pressure loss contribution ranking result corresponding to that local region is within a preset ranking interval, or determine whether the pressure loss contribution level result corresponding to that local region is a preset high contribution level. When either of the above determination results is yes, that local region is also included in the candidate pressure loss region set. Through this step, the candidate pressure loss region set is obtained.

[0148] In some implementations, the preset high contribution level is the highest level value determined from the acoustic contribution level results. Specifically, firstly, the acoustic contribution percentages corresponding to all local regions are read and sorted in descending order of acoustic contribution percentage; then, based on a preset number of layers or a preset layer ratio, all local regions are divided into multiple contribution level layers; the contribution level corresponding to the local region located in the first layer interval is determined as the preset high contribution level. Further, when a three-level layering method is used, all local regions are divided into high contribution level, medium contribution level, and low contribution level, where the high contribution level is determined as the preset high contribution level; when a multi-level layering method is used, the first-ranked contribution level with the largest corresponding acoustic contribution percentage is determined as the preset high contribution level. The preset high contribution level determined in this way is used to supplement the screening of local regions with relatively prominent impact on acoustic attenuation of the target frequency band from the perspective of level, in addition to acoustic contribution percentage and sorting position.

[0149] In some implementations, the preset pressure loss percentage threshold is determined based on the distribution of pressure loss contribution percentages across all local regions. Specifically, the pressure loss contribution percentages of all local regions are first read and sorted in descending order to obtain a pressure loss contribution percentage sorting sequence. Then, a preset proportion interval is read, and the corresponding last position in the pressure loss contribution percentage sorting sequence is determined based on the preset proportion interval. Subsequently, the pressure loss contribution percentage at the last position is extracted and determined as the preset pressure loss percentage threshold. The preset pressure loss percentage threshold determined in this way is used to filter out local regions that have a relatively prominent impact on overall pressure loss from all local regions. In some implementations, when the pressure loss contribution percentages of multiple local regions are the same as the pressure loss contribution percentage at the last position, the pressure loss contribution percentages of these multiple local regions are uniformly used as the basis for determining the value of the preset pressure loss percentage threshold.

[0150] In some implementations, the preset sorting interval corresponding to the pressure loss contribution ranking is used to limit the sorting range that can be included in the candidate pressure loss region set. Specifically, firstly, the pressure loss contribution ranking results corresponding to all local regions are read, and the total number of rankings is determined; then, based on a preset screening ratio or a preset screening quantity, the starting position and the ending position of the ranking are determined; the sorting range between the starting position and the ending position is determined as the preset sorting interval corresponding to the pressure loss contribution ranking. The preset sorting interval determined in this way is used to further supplement the screening of local regions with a high impact on the overall pressure loss based on the ranking position when the pressure loss contribution ratio does not reach the preset pressure loss ratio threshold. In some implementations, when the ranking ending position corresponding to the preset screening ratio is not an integer, the corresponding ranking ending position is rounded up to ensure that local regions near the critical position are not missed.

[0151] Step S503: Determine the candidate acoustic region set based on the joint contribution information corresponding to each local region. Specifically, for each local region, read the acoustic contribution percentage, acoustic contribution ranking result, and acoustic contribution level result corresponding to that local region. First, compare the acoustic contribution percentage corresponding to that local region with a preset acoustic contribution percentage threshold. When the acoustic contribution percentage corresponding to that local region is greater than or equal to the preset acoustic contribution percentage threshold, include that local region in the candidate acoustic region set. When the acoustic contribution percentage corresponding to that local region is less than the preset acoustic contribution percentage threshold, further determine whether the acoustic contribution ranking result corresponding to that local region is within a preset ranking interval, or determine whether the acoustic contribution level result corresponding to that local region is a preset high contribution level. When either of the above determination results is yes, that local region is also included in the candidate acoustic region set.

[0152] In some implementations, the preset acoustic proportion threshold is determined based on the distribution of acoustic contribution proportions across all local regions. Specifically, the acoustic contribution proportions of all local regions are first read and sorted in descending order to obtain a sorted sequence. Then, a preset proportion interval is read, and the corresponding last position is determined within the sorted sequence based on this interval. Subsequently, the acoustic contribution proportion at the last position is extracted and used as the preset acoustic proportion threshold. This preset acoustic proportion threshold is used to filter out local regions with a relatively significant impact on acoustic attenuation in the target frequency band from all local regions. In some implementations, when the acoustic contribution proportions of multiple local regions are the same as the acoustic contribution proportion at the last position, these multiple local regions are uniformly used as the basis for determining the preset acoustic proportion threshold.

[0153] Step S504: Determine an overlapping local region set based on the candidate pressure loss region set and the candidate acoustic region set. Specifically, read all region identifiers in the candidate pressure loss region set and read all region identifiers in the candidate acoustic region set; using each region identifier in the candidate pressure loss region set as the first search object, search for the existence of the same region identifier in the candidate acoustic region set one by one; when a certain region identifier exists in both the candidate pressure loss region set and the candidate acoustic region set, include the local region corresponding to the region identifier into the overlapping local region set.

[0154] Step S505: Determine conflict coupling zones based on the set of overlapping local regions. Specifically, read the spatial range of each overlapping local region and determine whether any two overlapping local regions satisfy any of the following spatial connection conditions: the first condition is sharing the same regional boundary; the second condition is that the termination position of one region along the main flow direction is connected to the starting position of the next region. When two or more overlapping local regions satisfy any spatial connection condition, merge the two or more overlapping local regions into one conflict coupling zone. When an overlapping local region does not satisfy the above spatial connection conditions with other overlapping local regions, determine the overlapping local region as a separate conflict coupling zone. Subsequently, assign a unique conflict zone identifier to each conflict coupling zone and record the set of local region identifiers and spatial range corresponding to the conflict zone identifier.

[0155] Furthermore, to illustrate the process of determining the candidate pressure loss region set, the candidate acoustic region set, and the conflict coupling region, for example:

[0156] Assuming that after completing steps S20 and S40, the pressure loss contribution percentages of local regions E1 to E5 are 28%, 22%, 14%, 20%, and 16%, respectively, and the corresponding acoustic contribution percentages are 10%, 24%, 27%, 21%, and 18%, respectively; if the preset pressure loss percentage threshold is determined to be 20% based on the distribution of pressure loss contribution percentages of all local regions, and the preset acoustic contribution percentage threshold is determined to be 21% based on the distribution of acoustic contribution percentages of all local regions, then local regions E1, E2, and E4 meet the preset pressure loss contribution conditions and can be included as candidates. The set of pressure loss regions; local regions E2, E3, and E4 meet the preset acoustic contribution conditions and can be included in the candidate acoustic region set; therefore, after performing region identification overlap determination on the two sets, the overlapping local region set can be obtained, including local region E2 and local region E4; if the termination position corresponding to local region E2 is connected to the starting position corresponding to local region E4, and the two are continuously arranged along the main flow direction, then local region E2 and local region E4 are merged into the same conflict coupling region F1; if the two do not meet the spatial connection conditions, they are respectively determined as conflict coupling region F1 and conflict coupling region F2.

[0157] Step S506: Output the conflict coupling region; the conflict coupling region includes at least a conflict region identifier, a set of local region identifiers corresponding to the conflict region identifier, and a spatial range corresponding to the set of local region identifiers; in a preferred embodiment, it further includes the pressure loss contribution ratio and acoustic contribution ratio corresponding to each local region within the conflict coupling region; through steps S501 to S506, the process of performing overlap determination on each local region in the anechoic unit structure model based on the pressure loss contribution result and the acoustic contribution result, and determining the conflict coupling region that simultaneously meets the preset pressure loss contribution condition and the preset acoustic contribution condition is completed.

[0158] Step S60: Generate regional adjustment constraints based on the local structural parameters corresponding to the conflict coupling zone, and perform structural parameter optimization according to the regional adjustment constraints to generate the target optimized structural result;

[0159] The conflict coupling region is implemented on adjustable local structural parameters, generating regional adjustment constraints that limit the adjustment range and direction of the local structural parameters. Under the regional adjustment constraints, structural parameter optimization is performed to generate a target optimized structural result that simultaneously considers pressure loss and acoustic performance of the target frequency band.

[0160] In some implementations, the steps for generating the target optimized structure result include:

[0161] Step S601: Extract local structural parameters corresponding to each conflict coupling zone based on the conflict coupling zone. Specifically, for each conflict coupling zone, read the local region identifier set and spatial range corresponding to the conflict coupling zone; then, based on the local region identifier set and spatial range, extract one or more of the following parameters from the silencing unit structure model: local channel width parameter, local channel height parameter, local cavity length parameter, local cavity width parameter, local turning angle parameter, local flow guide component length parameter, and local perforation diameter parameter, as the local structural parameters corresponding to the conflict coupling zone.

[0162] Step S602: Based on the local structural parameters corresponding to each conflict coupling zone, determine the adjustment direction corresponding to each local structural parameter. Specifically, for each local structural parameter, first read the pressure loss contribution ratio and acoustic contribution ratio of each local area within the conflict coupling zone to which the local structural parameter belongs; then determine the influence of the change of the local structural parameter on the local flow channel size and the local acoustic action space: when increasing the local structural parameter can increase the local flow channel size or reduce the local turning degree, the direction of increasing the adjustment is determined as the direction of reducing pressure loss; when adjusting the local structural parameter in the direction of decreasing the local blockage reduces the local blockage degree, the direction of decreasing the local blockage is determined as the direction of reducing pressure loss; when increasing or decreasing the local structural parameter can enhance the local cavity effect, enhance the target frequency band attenuation path, or maintain the local resonance space, the corresponding change direction is determined as the direction of maintaining acoustic attenuation.

[0163] Subsequently, the proportions of pressure loss contribution and acoustic contribution within the conflict coupling region to which the local structural parameter belongs are compared: when the proportion of pressure loss contribution is greater than the proportion of acoustic contribution, the adjustment direction of the local structural parameter is determined to prioritize reducing pressure loss; when the proportion of acoustic contribution is greater than the proportion of pressure loss contribution, the adjustment direction of the local structural parameter is determined to prioritize maintaining acoustic attenuation; when both are in the high value range, the adjustment direction of the local structural parameter is determined to be the balance adjustment direction; through this step, the adjustment direction corresponding to each local structural parameter is obtained.

[0164] Step S603: Determine the parameter adjustment range corresponding to each local structural parameter based on the adjustment direction and original parameter value of each local structural parameter. Specifically, for each local structural parameter, read the original parameter value corresponding to the local structural parameter and determine the parameter change ratio according to the parameter type of the local structural parameter; then multiply the original parameter value by the parameter change ratio to obtain the maximum allowable change corresponding to the local structural parameter.

[0165] When the adjustment direction of the local structural parameter is to prioritize reducing pressure loss, if the increase of the local structural parameter corresponds to the expansion of the local channel, the weakening of the local bend, or the relief of the local blockage, then the range from the original parameter value to the original parameter value plus the maximum allowable change is determined as the parameter adjustment range; if the decrease of the local structural parameter corresponds to the relief of the local blockage, then the range from the original parameter value minus the maximum allowable change to the original parameter value is determined as the parameter adjustment range.

[0166] When the adjustment direction of the local structural parameter is to prioritize maintaining the acoustic attenuation direction, the small fluctuation range of the original parameter value is determined as the parameter adjustment range; the small fluctuation range is obtained by multiplying the original parameter value by a preset small ratio.

[0167] When the adjustment direction of the local structural parameter is the balance adjustment direction, the preset adjustment interval that is symmetrical about the original parameter value is determined as the parameter adjustment range; the preset adjustment interval is obtained by multiplying the original parameter value by the preset balance ratio; through this step, the parameter adjustment range corresponding to each local structural parameter is obtained.

[0168] Step S604: Generate regional adjustment constraints based on the adjustment direction and parameter adjustment range corresponding to each local structural parameter. Specifically, for each conflict coupling region, establish a correspondence between all local structural parameters corresponding to the conflict coupling region, the adjustment direction corresponding to each local structural parameter, and the parameter adjustment range corresponding to each local structural parameter to form the regional adjustment constraints corresponding to the conflict coupling region; then summarize the regional adjustment constraints corresponding to all conflict coupling regions to generate regional adjustment constraints; the regional adjustment constraints include at least the local structural parameter identifier, adjustment direction, and parameter adjustment range.

[0169] Step S605: Generate candidate structural parameter combinations based on the region adjustment constraints. Specifically, for each local structural parameter, read its corresponding parameter adjustment range and preset parameter step size; take the starting value of the parameter adjustment range as the first candidate parameter value, and continuously add the preset parameter step size to the previous candidate parameter value until multiple candidate parameter values ​​are obtained that are less than or equal to the end value of the parameter adjustment range; when the last candidate parameter value is less than the end value of the parameter adjustment range, add the end value of the parameter adjustment range to the multiple candidate parameter values ​​to obtain the candidate parameter value set corresponding to the local structural parameter; then select one candidate parameter value from the candidate parameter values ​​corresponding to each local structural parameter, and combine the selected candidate parameter values ​​according to the correspondence of the local structural parameters to generate multiple candidate structural parameter combinations, and repeat this operation for all possible combinations to generate multiple candidate structural parameter combinations; wherein, each candidate structural parameter combination satisfies the adjustment direction and parameter adjustment range requirements of the corresponding local structural parameter.

[0170] Step S606: Generate candidate silencing unit structure models based on the candidate structural parameter combinations. Specifically, each candidate structural parameter combination is written back into the original silencing unit structure model. The original parameter values ​​of the corresponding local structural parameters in the original silencing unit structure model are replaced with the parameter values ​​corresponding to the candidate structural parameter combinations, while keeping other structural parameters not included in the optimization unchanged, to obtain candidate silencing unit structure models that correspond one-to-one with each candidate structural parameter combination.

[0171] Step S607: Based on the candidate silencing unit structure models, determine the performance evaluation results corresponding to each candidate silencing unit structure model. Specifically, for each candidate silencing unit structure model, repeat the fluid numerical simulation process corresponding to step S10 and the acoustic simulation process corresponding to step S30 to obtain the local pressure loss distribution results and target frequency band acoustic response results corresponding to the candidate silencing unit structure model. Then, based on the local pressure loss distribution results corresponding to the candidate silencing unit structure model, read the segment pressure drop values ​​corresponding to all segments and perform accumulation to obtain the overall cumulative pressure drop value corresponding to the candidate silencing unit structure model. At the same time, based on the target frequency band acoustic response results corresponding to the candidate silencing unit structure model, read the target frequency band average attenuation value to obtain the target frequency band average attenuation value corresponding to the candidate silencing unit structure model. Then, establish a correspondence between the overall cumulative pressure drop value and the target frequency band average attenuation value to form the performance evaluation results corresponding to the candidate silencing unit structure model. Through this step, the performance evaluation results corresponding to each candidate silencing unit structure model are obtained.

[0172] Step S608: Based on the performance evaluation results, determine the target optimized structure result. Specifically, first, read the overall cumulative voltage drop value and the average attenuation value of the target frequency band corresponding to each candidate anechoic unit structure model, and select candidate anechoic unit structure models that simultaneously meet the preset cumulative voltage drop requirement and the preset target frequency band attenuation requirement to form a feasible candidate set; then, sort the candidate anechoic unit structure models in the feasible candidate set in ascending order of overall cumulative voltage drop value; when the overall cumulative voltage drop values ​​corresponding to two adjacent candidate anechoic unit structure models are the same, or the difference between the two is less than the preset voltage drop difference threshold, then reorder the two candidate anechoic unit structure models in descending order of target frequency band average attenuation value; finally, determine the candidate anechoic unit structure model that is ranked first as the target optimized structure result.

[0173] Step S609 outputs the region adjustment constraints and the target optimized structure result. The target optimized structure result includes at least the optimized anechoic unit structure model and the local structural parameter values ​​corresponding to the optimized anechoic unit structure model. In a preferred embodiment, it further includes the corresponding overall cumulative voltage drop value and the target frequency band average attenuation value. Through steps S601 to S609, the process of generating region adjustment constraints based on the local structural parameters corresponding to the conflict coupling region and performing structural parameter optimization according to the region adjustment constraints to generate the target optimized structure result is completed.

[0174] In some implementations, to illustrate the candidate structure selection process under region adjustment constraints, for example:

[0175] Assume the conflict coupling zone F1 includes a local channel width parameter G1 and a local cavity length parameter G2. The original value of the local channel width parameter G1 is 42 mm, and the original value of the local cavity length parameter G2 is 96 mm. If, based on a comparison of the pressure loss contribution ratio and the acoustic contribution ratio, the adjustment direction of the local channel width parameter G1 is determined to prioritize reducing pressure loss, and the corresponding parameter change ratio is set at 10%, then the maximum allowable change in the local channel width parameter G1 is 4.2 mm. Its parameter adjustment... The overall range can be determined to be 42 mm to 46.2 mm; if the adjustment direction of the local cavity length parameter G2 is the balance adjustment direction, and the preset balance ratio is determined to be 6%, then the maximum allowable change of the local cavity length parameter G2 is 5.76 mm, and its parameter adjustment range can be determined to be 90.24 mm to 101.76 mm; furthermore, when the preset parameter step size of the local channel width parameter G1 is 1 mm, and the preset parameter step size of the local cavity length parameter G2 is 2 mm, the candidate parameter value set {42, 4...} can be formed respectively. The set of candidate parameter values ​​{3, 44, 45, 46} and G2 {90.24, 92.24, 94.24, 96.24, 98.24, 100.24} are used to generate multiple candidate structural parameter combinations. Assume that the overall cumulative voltage drop values ​​corresponding to three candidate anechoic unit structural models are 4.8 kPa, 4.6 kPa, and 4.6 kPa, respectively, and the corresponding average attenuation values ​​in the target frequency band are 10.9 dB, 10.4 dB, and 11.1 dB, respectively. If the preset cumulative voltage drop requirement is no higher than 5.0 kPa, the preset target... The attenuation requirement for the target frequency band is no less than 10.3 dB, so all three candidate anechoic unit structural models meet the screening criteria. Furthermore, after sorting the three candidate anechoic unit structural models according to their total cumulative voltage drop value from smallest to largest, it can be found that the last two candidate anechoic unit structural models have the same total cumulative voltage drop value. Therefore, they are then re-sorted according to the average attenuation value of the target frequency band from largest to smallest. Finally, the candidate anechoic unit structural model with a total cumulative voltage drop value of 4.6 kPa and an average attenuation value of 11.1 dB in the target frequency band can be determined as the target optimized structural result.

[0176] In some implementations, the parameter change ratio is determined based on the processing adjustable range or design allowable variation range of the corresponding local structural parameter. Specifically, the original parameter value and the upper limit of allowable variation of the corresponding local structural parameter are read, and the ratio of the difference between the upper limit of allowable variation and the original parameter value to the original parameter value is determined as the parameter change ratio.

[0177] In some implementations, the preset small-amplitude ratio is used to limit the allowable fluctuation range of local structural parameters while maintaining the acoustic attenuation direction. Specifically, the original parameter value corresponding to the current local structural parameter is first read, and the maximum adjustable ratio of the local structural parameter within the design allowable range is read; then, a smaller ratio value is selected from the maximum adjustable ratio and determined as the preset small-amplitude ratio. The preset small-amplitude ratio determined in this way allows the local structural parameters to be adjusted only within a small range while maintaining the acoustic attenuation effect of the target frequency band, thereby reducing the risk of damage to the original acoustic attenuation path.

[0178] In some implementations, the preset parameter step size is determined based on the resolution requirements of the corresponding local structural parameter; specifically, when the corresponding local structural parameter is a size parameter, the preset parameter step size is determined based on the resolution requirements of size changes; when the corresponding local structural parameter is an angle parameter, the preset parameter step size is determined based on the resolution requirements of angle changes; when the corresponding local structural parameter is a perforation parameter, the preset parameter step size is determined based on the resolution requirements of aperture changes.

[0179] In some implementations, the preset voltage drop difference threshold is used to determine whether the overall cumulative voltage drop values ​​corresponding to two candidate anechoic unit structure models are close. Specifically, the overall cumulative voltage drop values ​​corresponding to all candidate anechoic unit structure models are first read, and the difference between the overall cumulative voltage drop values ​​corresponding to adjacent sorting positions is calculated. Then, based on the difference distribution results, the smaller difference range is selected as the preset voltage drop difference threshold. The preset voltage drop difference threshold determined in this way can be used to further perform a secondary sorting based on the average attenuation value of the target frequency band when the overall cumulative voltage drop values ​​corresponding to multiple candidate anechoic unit structure models are the same or close.

[0180] Example 2

[0181] See Figure 3 As shown, this embodiment provides a CFD conflict coupling region identification and optimization system for exhaust muffler units. Since this system uses an exhaust muffler unit CFD conflict coupling region identification and optimization method from Embodiment 1, it also has the same effect, which will not be repeated here. The system includes:

[0182] The pressure loss distribution generation module is used to obtain the structural model and boundary conditions of the muffler unit of the target exhaust system under set operating conditions, and to perform fluid numerical simulation to generate local pressure loss distribution results.

[0183] The pressure loss contribution determination module determines the pressure loss contribution results for each local region in the silencing unit structure model based on the local pressure loss distribution results.

[0184] The acoustic response generation module performs acoustic simulation based on the silencing unit structure model and acoustic boundary conditions to generate acoustic response results for the target frequency band.

[0185] The acoustic contribution determination module determines the acoustic contribution results of each local region in the silencing unit structure model based on the acoustic response results of the target frequency band.

[0186] The conflict coupling zone determination module performs overlap determination on each local region in the anechoic unit structure model based on the pressure loss contribution result and the acoustic contribution result, and determines the conflict coupling zone that simultaneously meets the preset pressure loss contribution condition and the preset acoustic contribution condition.

[0187] The optimization result generation module generates regional adjustment constraints based on the local structural parameters corresponding to the conflict coupling zone, and performs structural parameter optimization according to the regional adjustment constraints to generate the target optimized structural result.

[0188] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope defined in the claims.

Claims

1. A method for identifying and optimizing the CFD conflict coupling region of an exhaust muffler unit, characterized in that, include: Obtain the structural model and boundary conditions of the muffler unit of the target exhaust system under set operating conditions, and perform fluid numerical simulation to generate local pressure loss distribution results; Based on the local pressure loss distribution results, the pressure loss contribution results corresponding to each local region in the silencing unit structure model are determined. Based on the aforementioned anechoic unit structure model and acoustic boundary conditions, acoustic simulation is performed to generate acoustic response results for the target frequency band. Based on the acoustic response results of the target frequency band, the acoustic contribution results of each local region in the silencing unit structure model are determined; Based on the pressure loss contribution result and the acoustic contribution result, overlap determination is performed on each local region in the silencing unit structure model to determine the conflict coupling zone that simultaneously meets the preset pressure loss contribution condition and the preset acoustic contribution condition; Based on the local structural parameters corresponding to the conflict coupling zone, a region adjustment constraint is generated, and structural parameter optimization is performed according to the region adjustment constraint to generate the target optimized structural result.

2. The method for identifying and optimizing the CFD conflict coupling region of an exhaust muffler unit according to claim 1, characterized in that, Methods for generating local pressure loss distribution results include: Based on the internal flow space corresponding to the silencing unit structure model, a set of computing units is generated. According to the boundary conditions, the fluid state parameters corresponding to each computing unit are initialized and iteratively updated to obtain the effective unit pressure value corresponding to each computing unit. The main flow direction is determined based on the spatial connection relationship between each computing unit and the effective flow velocity parameters. Segment combination is performed on multiple adjacent computing units along the main flow direction to obtain multiple location segments. The pressure drop value of each section is determined based on the effective unit pressure value corresponding to each location section. The section identifier, spatial location of each section and the corresponding pressure drop value are then linked to generate the local pressure loss distribution results.

3. The method for identifying and optimizing the CFD conflict coupling region of an exhaust muffler unit according to claim 2, characterized in that, Methods for determining the contribution of pressure loss include: Based on the anechoic unit structure model, the region boundary positions are extracted, and the anechoic unit structure model is divided into regions according to the region boundary positions to obtain each local region; Based on the results of local pressure loss distribution, the segment-region mapping relationship between each segment and each local region is determined, and based on the segment-region mapping relationship, the cumulative pressure drop value corresponding to each local region is determined. Based on the cumulative pressure drop value of each local area, the pressure loss contribution ratio, contribution ranking and contribution level of each local area are determined, and pressure loss contribution results are generated.

4. The method for identifying and optimizing the CFD conflict coupling region of an exhaust muffler unit according to claim 1, characterized in that, Methods for generating acoustic response results for the target frequency band include: Based on acoustic boundary conditions, the target frequency band range and entrance acoustic excitation parameters are determined; A set of discrete frequency points is generated based on the target frequency band range, and a set of acoustic solution units is generated based on the sound-absorbing unit structure model. The acoustic state parameters of each acoustic solution unit are initialized based on the entrance acoustic excitation parameters, and the acoustic state parameters of each acoustic solution unit are iteratively updated point by point at each discrete frequency point to obtain the effective unit sound pressure value at each discrete frequency point. The attenuation characterization value is determined based on the effective unit sound pressure value corresponding to each discrete frequency point, and the acoustic response result of the target frequency band is generated.

5. The method for identifying and optimizing the CFD conflict coupling region of an exhaust muffler unit according to claim 1, characterized in that, Methods for generating acoustic contribution results include: Based on the local structural parameters corresponding to each local region, the perturbed local structural parameters corresponding to each local region are generated, and based on the perturbed local structural parameters corresponding to each local region, the perturbed noise reduction unit structure model corresponding to each local region is generated. Based on the perturbation-induced noise reduction unit structure model corresponding to each local region, the acoustic simulation is re-executed to obtain the perturbation-induced acoustic response results of the target frequency band corresponding to each local region. Based on the acoustic response results of the target frequency band after disturbance and the acoustic response results of the original target frequency band, the change in acoustic response, the proportion of acoustic contribution, the contribution ranking results and the contribution level results of each local region are determined, and the acoustic contribution results are generated.

6. The method for identifying and optimizing the CFD conflict coupling region of an exhaust muffler unit according to any one of claims 1-5, characterized in that, Methods for determining conflict coupling regions include: Based on the pressure loss contribution results and acoustic contribution results, the joint contribution information corresponding to each local region is determined; Based on the joint contribution information corresponding to each local region, a set of candidate pressure loss regions is determined according to the preset pressure loss contribution conditions, and a set of candidate acoustic regions is determined according to the preset acoustic contribution conditions. Based on the candidate pressure loss region set and the candidate acoustic region set, the set of overlapping local regions is determined; Based on the spatial connection relationship between local regions in the set of overlapping local regions, multiple overlapping local regions that meet the spatial connection conditions are merged to determine the conflict coupling zone.

7. The method for identifying and optimizing the CFD conflict coupling region of an exhaust muffler unit according to claim 6, characterized in that, Methods for generating region adjustment constraints include: Extract local structural parameters corresponding to each conflict coupling region based on the conflict coupling region; Based on the proportion of pressure loss contribution and acoustic contribution within the conflict coupling zone of each local structural parameter, the adjustment direction corresponding to each local structural parameter is determined. Based on the adjustment direction and original parameter value of each local structural parameter, determine the parameter adjustment range of each local structural parameter; Establish a correspondence between the local structural parameters corresponding to each conflict coupling zone, the adjustment direction corresponding to each local structural parameter, and the parameter adjustment range corresponding to each local structural parameter, and generate regional adjustment constraints.

8. The method for identifying and optimizing the CFD conflict coupling region of an exhaust muffler unit according to claim 7, characterized in that, Methods for generating target optimization structure results include: Candidate structural parameter combinations are generated based on region adjustment constraints, and candidate noise reduction unit structural models are generated based on the candidate structural parameter combinations. Based on the structural models of each candidate noise reduction unit, fluid numerical simulation and acoustic simulation are performed respectively to determine the overall cumulative pressure drop value and the average attenuation value of the target frequency band corresponding to each candidate noise reduction unit structural model, and to generate performance evaluation results. Based on the performance evaluation results, candidate noise reduction unit structure models that simultaneously meet the preset cumulative voltage drop requirements and the preset target frequency band attenuation requirements are selected, and the candidate noise reduction unit structure model ranked first is determined as the target optimized structure result.

9. The method for identifying and optimizing the CFD conflict coupling region of an exhaust muffler unit according to claim 6, characterized in that, The methods for determining the preset pressure loss contribution condition and the preset acoustic contribution condition include: Read the pressure loss contribution ratio and acoustic contribution ratio of all local regions respectively and sort them. Determine the preset pressure loss ratio threshold and preset acoustic ratio threshold according to the preset ratio range. Based on the preset screening ratio or preset screening quantity, determine the preset sorting intervals corresponding to the pressure loss contribution ranking results and the acoustic contribution ranking results, respectively. Based on the pressure loss contribution level results and the acoustic contribution level results, the corresponding preset high contribution levels are determined respectively; The following conditions are defined as the preset pressure loss contribution conditions: the pressure loss contribution ratio of the local area is greater than or equal to the preset pressure loss ratio threshold, the pressure loss contribution ranking result is within the preset ranking interval, and the pressure loss contribution level result is the preset high contribution level. The preset acoustic contribution conditions are determined by any one of the following: the acoustic contribution ratio of a local area is greater than or equal to a preset acoustic contribution threshold, the acoustic contribution ranking result is within a preset ranking interval, or the acoustic contribution level result is a preset high contribution level.

10. A CFD conflict coupling region identification and optimization system for an exhaust muffler unit, characterized in that, include: The pressure loss distribution generation module is used to obtain the structural model and boundary conditions of the muffler unit of the target exhaust system under set operating conditions, and to perform fluid numerical simulation to generate local pressure loss distribution results. The pressure loss contribution determination module determines the pressure loss contribution results for each local region in the silencing unit structure model based on the local pressure loss distribution results. The acoustic response generation module performs acoustic simulation based on the silencing unit structure model and acoustic boundary conditions to generate acoustic response results for the target frequency band. The acoustic contribution determination module determines the acoustic contribution results of each local region in the silencing unit structure model based on the acoustic response results of the target frequency band. The conflict coupling zone determination module is used to perform overlap determination on each local region in the anechoic unit structure model based on the pressure loss contribution result and the acoustic contribution result, and determine the conflict coupling zone that simultaneously meets the preset pressure loss contribution condition and the preset acoustic contribution condition. The optimization result generation module generates regional adjustment constraints based on the local structural parameters corresponding to the conflict coupling zone, and performs structural parameter optimization according to the regional adjustment constraints to generate the target optimized structural result.

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